Creating Drawings

Overview

Students learn to create professional technical drawings in OnShape by generating 2D views from a 3D model and applying clear dimensioning. The lesson connects geometric construction ideas (conditions that determine shapes) to how technical drawings communicate exact measurements.

Learning intentions

Students will be able to:

• Draw and label 2D views of a 3D object using a digital CAD tool.
• Use scale and dimensions consistently to reproduce measurements accurately.
• Determine whether given drawing conditions imply a unique 2D layout (e.g., matching angles/sizes) or multiple possibilities.
• Communicate construction intent clearly using standard technical drawing conventions.

Success criteria

• I can generate at least three standard views (front, top, side or equivalents) from my 3D model.
• I can place accurate dimensions and labels so someone else can recreate my 2D drawing.
• I can explain how scale and measurement units affect the final drawing.
• I can check my drawing to see if the given measurements “force” a single correct drawing or allow multiple shapes.

Curriculum links

• Geometry — drawing geometric shapes with given conditions (single vs multiple vs no solution), and using tools like ruler/protractor/technology.
• Geometry — solving problems involving scale drawings, including computing actual lengths and reproducing a scale drawing at a different scale.
• Geometry — slicing 3D figures to describe 2D plane sections (views are plane sections of 3D solids).
• Mathematical practice — using appropriate tools strategically, including technology, and recognizing limitations.

Lesson structure (45 minutes)

1. 0–5 min · Warm-up (Draw-to-Think). Teacher displays two quick scenarios on the board: “Given 3 angle measures: can you form a triangle?” and “Given two angles and one side: what happens?” Students pair-share whether a unique drawing is possible and why.

2. 5–12 min · Mini-Direct Teach (From 3D to 2D). Teacher demonstrates in OnShape: open a prior model from Lesson 13, then create orthographic views (front/top/side) and zoom/pan to confirm alignment. Students follow along on their devices using the same model template.

3. 12–20 min · Guided Practice (Create required views). Teacher gives a checklist: create 3 views, ensure each view is orthographic, and place them in a clean layout on the drawing sheet. Students complete the three views and confirm each view matches the 3D model orientation.

4. 20–30 min · Guided Practice (Dimensioning and units). Teacher models dimension placement: choose key lengths, set units, and avoid clutter (dimension the features that fully describe the shape). Students add dimensions to their drawings, aiming to describe the model’s essential geometry so another student could recreate it.

5. 30–38 min · Scale Connection (Measure & verify). Teacher introduces a simple scale factor question using the drawing: “If the drawing uses a scale of 2:1, what is the actual length for a 25 mm dimension on the drawing?” Students calculate actual lengths and then compare with their model’s real dimensions inside OnShape to verify consistency.

6. 38–44 min · Quick Check (Unique vs multiple drawing reasoning). Teacher prompts: “If you only know two lengths but not their included angle/relationship, does the drawing have one solution or many?” Students write a 2–3 sentence justification on a small “Technical Drawing Proof” card and attach it to their device or submit digitally.

7. 44–45 min · Exit Ticket (One task, fast). Students answer: “List one dimension that is essential for uniqueness and one dimension you could leave out without losing the main shape.” Collect before dismissal.

Resources

• Chromebooks/laptops with OnShape access for each student
• A saved OnShape part from Lesson 13 for each student (or class starter model)
• Printed or digital “3 Views + Dimensions Checklist”
• “Technical Drawing Proof” card (half-sheet) with the unique/multiple prompt
• Exit ticket slips
• Teacher sample images/screenshots of correctly dimensioned drawings
• Optional: simple ruler and protractor for a brief analogy (not for CAD work)

Assessment

• Formative: Teacher circulates during view creation, checking that views are orthographic and correctly positioned.
• Formative: Teacher checks dimension choices for completeness and clarity (essential dimensions vs decorative dimensions).
• Formative: Scale verification question at the board—students show answers and reasoning quickly.
• Exit ticket: assesses understanding of uniqueness and essential dimensions.

Differentiation

• Support: Provide sentence starters on the “Technical Drawing Proof” card (e.g., “A unique drawing requires…” “Multiple drawings are possible because…”).
• Support: Offer a “Minimum Dimensions” example list for students who need help identifying essential features.
• Extension: Students who finish early can improve drawing quality by adding title block details, alignment/spacing polish, and verifying dimensions against the 3D model with a final check.
• EAL/SEN: Reduce cognitive load by limiting the number of required dimensions (e.g., 6–8 key dimensions) and emphasizing consistent units and clear labeling.